TB 9-6670-254-50
NOTE
A sensitivity weight must be chosen for each different weight to
be calibrated since sensitivity of balance changes with different
weight loads.
(6) Place sensitivity weight on appropriate pan so that balance pointer will oscillate
and remain on scale.
NOTE
If necessary, a small incremental weight may-be added to
appropriate pan to cause oscillations. This weight is to remain
with weight added to, when transposed.
(7) Repeat (3) above. A total of three observations is now recorded with five turning
points for each observation
(8) Select last three turning points of each observation recorded on worksheet and
average, using formula below:
4
each observation (01, 02, 03). Subscripts 01, 02, and 03 indicate the order in which observations
occurred).
(9) Compute value of TI weight, using the following formula:
A = B + K (01 02)
2
Where A = Value of TI weight
B = Value of standard weight
K=
m
03 - 02
M = Value of sensitivity weight
EXAMPLE:
The following example was taken from a special purpose weight calibration problem using the single
transposition method with a large double pan balance.
Standard weight (B) made by summing standard S-1 weights was equal to 44.800 lbs, the
approximate nominal value of the test weight. An S-1 sensitivity weight (M) of 0.005 lb was chosen.
01 = TIT32T2
=
R1R2-2L1
4
4
3.5 3 - 2(3)
= 0.125
4
Similarly:
02 = -0.25 and
03 = 0.3125
(continued)